Armor Stability on Submerged Breakwaters

Abstract

Armor stability on submerged conventional breakwaters is examined using a hybrid method based on experimental, numerical, and empirical results. Four test runs are conducted to measure the horizontal fluid velocities and free-surface elevations over a submerged breakwater caused by a solitary wave. These measurements are used to evaluate the numerical model called IBREAK. The agreement between the measured and computed results is found to be fair except that IBREAK overestimates the velocities immediately landward of the crest of the submerged breakwater for the case of small submergence. The comparison also shows that the horizontal velocity over the breakwater decreases with the increase of its submergence. The reduction of the horizontal velocity is then related to the increase of armor stability on the breakwater with the increase of its submergence. The present method predicts the significant increase of the armor stability resulting from the moderate reduction of the maximum horizontal velocity with the increase of the submergence depth. Comprehensive data are required to verify the predicted armor stability.